---
id: CVE-2026-115384
title: Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 Stack Buffer Overflow
summary: >-
  Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a stack buffer
  overflow vulnerability that allows malicious guests to write ~16KB to the
  native stack via unvalidated async callback result types. Attackers can supply
  compo…
severity: critical
cvss: 9.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-20
vendor: bytecodealliance
product: wasmtime
affected:
  - wasmtime >= 39.0.0 < 48.0.4
  - wasmtime >= 49.0.0 < 49.0.2
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T19:13:51.422Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115384'
references:
  - url: >-
      https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-32h6-97mm-8q3c
    label: GitHub Security Advisory (GHSA-32h6-97mm-8q3c)
  - url: >-
      https://www.vulncheck.com/advisories/wasmtime-39.0.0-before-48.0.4-and-49.0.0-before-49.0.2-stack-buffer-overflow
    label: >-
      VulnCheck Advisory: Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2
      Stack Buffer Overflow
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.404Z'
---

## Overview

Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a stack buffer overflow vulnerability that allows malicious guests to write ~16KB to the native stack via unvalidated async callback result types. Attackers can supply components with mistyped component-model-async callback functions to overwrite return addresses, crashing the host or escaping the sandbox.

## Affected

- `wasmtime >= 39.0.0 < 48.0.4`
- `wasmtime >= 49.0.0 < 49.0.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.